1. Field of the Invention
The present invention relates to a MIMO (Multiple Input Multiple Output) antenna including a plurality of antenna elements, and a wireless device. 2. Description of the Related Art
In the field of communication devices such as mobile terminals where an adequate distance cannot be secured between antenna elements, there is a demand for a MIMO antenna with a high antenna gain and a low correlation coefficient between antenna elements in order to ensure good MIMO effects. The MIMO antenna is a multi-antenna that is capable of multiple-input and multiple-output operations at a predetermined frequency using a plurality of antenna elements. For example, Japanese Laid-Open Patent Publication No. 2010-130115 discloses a MIMO antenna including a plurality of monopole antenna elements that utilize a ground plane as a MIMO antenna including a plurality of antennal elements.
In MIMO antennas, the correlation coefficient between antenna elements has to be lowered. However, in MIMO antennas that use monopole antenna elements, the correlation coefficient cannot be lowered unless the monopole antenna elements are released from the ground plane. When the monopole antenna elements are released from the ground plane, the space required for installing the antenna elements is expanded, and as such, it is difficult to reduce the installation space of the antenna elements and lower the correlation coefficient between the antenna elements at the same time.